Abstract: A method of reducing the emanation of radon gas from radium in mine rock faces. Also disclosed is apparatus employing an anode in electrical contact with the mine rock face in a water-bearing formation and a cathode remote therefrom in the water-bearing formation, as well as a source of D-C voltage for applying a potential between the cathode and the anode for moving radium ions toward the cathode through the water-bearing formation from the mine rock face by electrolysis.

Abstract: A debilitating agent is injected into a subterranean formation under conditions of time and injection rates such that it permeates both the more permeable zones and the less permeable zones. A flush is then injected under conditions of time and rate so as to selectively remove the debilitating agent from the more permeable zones. In one embodiment the debilitating agent is a polymerization inhibitor or poison. Then a material which will polymerize in the absence of the poison or inhibitor is injected. Since the poison or inhibitor will remain in the less permeable zones, little or no polymer is formed there. In the more permeable zones from which the poison has been flushed, polymerization occurs so that subsequently injected secondary or tertiary oil recovery fluids are diverted away from the thief zones to more effectively displace the oil from the less permeable zones.